Metal matrix composites (MMCs) are currently being investigated because of their superior properties. The properties are mainly attributed to the efficiency of the load transfer from the matrix to the reinforcements through the ma-trix-reinforcement interface. The aim of this study is to investigate the effect of manufacturing parameters on the micro-structure and morphology of the interface and the aluminide phases formed at the matrix-reinforcement interfaces. The parameters are: milling time to fabricate Ni3Al, method of mixing of Ni3Al and Al powders, compaction pressure and sintering temperature. The composite studied in this research was Al/5 Vol% Ni3Al made from two different types of Ni3Al powders. The results showed that compacting and sintering at higher levels lead to the transformation of Ni3Al particles to thin layers of Al3Ni. It was also shown that the prolonged milling time to produce Ni3Al reinforcements and the prolonged ball milling procedure for mixing the powders, both, promote the diffusion process at reinforcement/ma-trix interface.